Re: [PATCH] bpf: Fix infinite loop in pcpu_freelist push with one possible CPU

From: patchwork-bot+netdevbpf

Date: Thu Aug 20 2026 - 14:51:30 EST


Hello:

This patch was applied to bpf/bpf.git (master)
by Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>:

On Fri, 7 Aug 2026 01:56:00 +0800 you wrote:
> __pcpu_freelist_push() can loop forever when only one CPU is possible
> and an NMI re-enters pcpu_freelist_push() while the interrupted context
> holds that CPU's freelist lock.
>
> After the current-CPU fast path fails, the fallback loop walks
> cpu_possible_mask while skipping the current CPU. With CONFIG_SMP=n, or
> when an SMP kernel is limited to one possible CPU with nr_cpus=1 or
> possible_cpus=1, there are no other possible CPUs to examine. The loop
> therefore makes no lock acquisition attempt and can never make progress.
>
> [...]

Here is the summary with links:
- bpf: Fix infinite loop in pcpu_freelist push with one possible CPU
https://git.kernel.org/bpf/bpf/c/efebf6496685

You are awesome, thank you!
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